The present invention relates to optical devices, and more particularly, to a reconfigurable optical add/drop multiplexer (ROADM) applied to optical transmission networks.
A conventional optical add/drop multiplexer (OADM), as shown in FIG. 1, is widely applied to optical transmission networks for adding or dropping optical wavelength signals at network nodes for data exchange. In response to increase in number of available wavelengths for each optical fiber in the optical transmission networks, the optical add/drop multiplexer should be designed to be capable of processing a wider range of wavelengths. Optical add/drop multiplexers are generally classified as fixed-type OADMs and reconfigurable-type OADMs (ROADMs). A fixed-type OADM transmits an upstream or downstream signal of a fixed wavelength at a network node, and a ROADM regulates the wavelength of the upstream or downstream signal at the network node, so as to evenly distribute network wavelength resources and thus to improve network dataflow capacity.
Therefore, ROADMs that provide dynamic reconfiguring ability for optical transmission networks, thus become actively-developed products by manufacturers.
A primary objective of the present invention is to provide a ROADM optical device applicable to an optical transmission network, which ROADM optical device is assembled by at least a fiber collimator, a filter, and an optical element for forming a 2xc3x972 optical path switch.
In accordance with the above and other objectives, the present invention provides an optical device, comprising: a first input end for receiving a multiple-wavelength optical signal, wherein the multiple-wavelength optical signal includes an optical signal to be dropped, and the first input end has a first filter that is capable of isolating the optical signal to be dropped, from the multiple-wavelength optical signal; a second input end for receiving an optical signal to be added, which has the same wavelength as the optical signal to be dropped; a first output end; a second output end coupled to the first input end, and having a second filter for allowing the optical signal to be dropped and the optical signal to be added to pass therethrough; and a switching member.
When the switching member is situated at a first position, the first output end outputs the optical signal to be dropped that passes through the first filter, and the second output end outputs the optical signal to be added and the multiple-wavelength optical signal exclusive of the optical signal to be dropped. When the switching member is situated at a second position, the second output end outputs the multiple-wavelength optical signal exclusive of the optical signal to be dropped and the optical signal to be dropped that passes through the first filter, and the first output end outputs the optical signal to be added.